Verapamil, a calcium channel blocking agent, has been shown to be an effective new therapeutic agen for the treatment of patients with hypertrophic cardiomyopathy. in order to determine whether other drugs of this type will be equally effective, nifedipine was compared with verapamil and placebo administration in a double-blind randomized study. Results indicate that both verapamil and nifedipine can improve exercise capacity and symptomatic status in patients with hypertrophic cardiomyopathy, but patients must be carefully chosen because serious adverse drug effects can occur. Although verapamil seems to be more effective than nifedipine in the treatment of this disorder, nifedipine may be helpful in patients who do not tolerate or respond to verapamil.